<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>检查 Set 中存在某个 value，编写对应函数</title>
</head>
<body>
    
</body>
</html>
<script>
    var set = new Set([1,0,2,4,,5]);
    console.log(set.has(6));    //false
    console.log(set.has(5));    //ture
</script>